#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>
void error_handling(char *message);

int main(int argc ,char *argv[]){
    int serv_sock;
    int clnt_sock;
    
    struct sockaddr_in serv_addr;
    struct sockaddr_in clnt_addr;
    //socklen_t clnt_addr_size;
    int clnt_addr_size;
    
    char message[] = "hello world!";
    
    // if(argc!=2){
    // printf("Usage:%s <port>\n",argv[0]);
    // exit(0);
    // }   

    serv_sock = socket(PF_INET,SOCK_STREAM,0);
    if(serv_sock==-1) error_handling("socket() error");
    
    memset(&serv_addr,0,sizeof(serv_addr));
    serv_addr.sin_family=AF_INET;
    serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
    //serv_addr.sin_port=htons(atoi(argv[1]));
    serv_addr.sin_port = htons(9190);
    if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1) 
    error_handling("bind() error");


    if(listen(serv_sock,5)==-1) error_handling("listen() error");
    clnt_addr_size=sizeof(clnt_addr);
    clnt_sock=accept(serv_sock,(struct sockaddr*)&clnt_addr,&clnt_addr_size);

    if(clnt_sock==-1) error_handling("accept() error");

    write(clnt_sock,message,sizeof(message));
    close(clnt_sock);
    close(serv_sock);
    return 0;
}
void error_handling(char *message){
    fputs(message,stderr);
    fputc('\n',stderr);
    exit(1);
}